The Arizona immigration case follows the outlines of the case over the Affordable Care Act: both pit the administration against conservative state governments; both create crucibles for the forging of a new definition of "activist judges"; and in debates over both policies, conservatives have used economic fears to stack the deck in what is really an argument about civil rights. Justice Antonin Scalia reliably withering dissent from Monday's ruling on the SB1070 law begins its conclusion with just such a feint:

Thousands of Arizona's estimated 400,000 illegal immigrants … are now assured immunity from enforcement, and will be able to compete openly with Arizona citizens for employment.

An opera fan, Scalia rather predictably ends his argument with a sweeping, melodramatic harrumph, the judicial equivalent of turning on his heels and storming out of the room:

"If securing its territory in this fashion is not within the power of Arizona, we should cease referring to it as a sovereign state. I dissent."

(You can almost hear his robes swishing behind him.)

Scalia defines sovereignty as "the power to exclude". That definition is the basis of his dissent and, one could argue, the defining attitude of modern Republican party, as well. With the rise of the Tea Party, the fracturing of their base, and their death grip on retrograde views on social issues, the GOP has been slowly cutting away at itself for at least the past four years.

And to be sure, Romney has given new meaning to the term "negative campaigning" with his refusal to positively assert his position on much of anything. On immigration, his statement was particularly vacant, allowing only that "each state has the duty – and the right – to secure our borders and preserve the rule of law, particularly when the federal government has failed to meet its responsibilities."

Allowing states – and individuals – to operate in the white space between the federal government's enumerated powers is the hallmark of the American experiment, but Arizona's law wasn't about filling in where federal government wasn't; the Arizona law attempted to go beyond the authority of the federal government. As Justice Anthony Kennedy noted drily in opinion, while federal allows states to "cooperate" with the US attorney general in immigration matters, "no coherent understanding of the term would incorporate the unilateral decision of state officers to arrest an alien" without "any request, approval, or other instruction from the federal government".

In other words: when we want your help, we'll ask for it. A tricky kind of negative instruction that obviously rubbed Scalia the wrong way.

An ardent originalist, Scalia wants the federal government to be in the position of waiting-to-be-asked. His nostalgia for the federal government's infancy, when states necessarily defined themselves independent of oversight is drenched in sepia tones so deep that he apparently can't register the racism therein. In one section, he approvingly cites how –

"in the first 100 years of the Republic, the states enacted numerous laws restricting the immigration of certain classes of aliens, including convicted criminals, indigents, persons with contagious diseases, and (in southern states) freed blacks."

I suppose that in creating a parallel between those exclusions and the Arizona law, he is not entirely wrong – though a lot has changed in the second and third centuries of the country's existence.

One is hard-pressed to find a citation in Scalia's dissent whose authors would have lived to see the telephone, much less the "E-verify" and database technology has allowed the court tentatively to uphold a single section of the Arizona legislation. That provision requires state officers to make a "'reasonable attempt … to determine the immigration status" of any person they stop, detain, or arrest on some other legitimate basis if "reasonable suspicion exists that the person is an alien and is unlawfully present in the United States". The court seem cautious about how the requirement means that –

"officers must make an inquiry even in cases where it seems unlikely that the attorney general would have the alien removed. This might be the case, for example, when an alien is an elderly veteran with significant and longstanding ties to the community."

The majority decision emphasizes the way that the Arizona law overdetermines the fate of those simply suspected of being illegal immigrants. Indeed, it is not difficult to imagine, and it seems to be the point, that enforcement of the law in its totality would give state officials the ability to detain anyone, for any length of time. (In Scalia's flippant interpretation, "I know of no reason why a protracted detention that does not violate the fourth amendment would contradict or conflict with any federal immigration law.")

But in the end, between access to immigration records "24 hours a day, seven days a week, 365 days a year" and a hopeful note that "section 2(B) could be read to avoid … concerns" about "detaining individuals solely to verify their immigration status", the supreme court's decision validates another kind of intentional negative space. The Arizona laws that it struck down return to state and federal officials the ability to judge individual situations they see before them. As Kennedy writes:

"Discretion in the enforcement of immigration law embraces immediate human concerns."

This seems like a loophole, but it is really ceding power to the most individual level – the ultimate act of governmental restraint. On the other hand, Scalia and his cohort of anti-immigration proponents clothe their argument in the rhetoric of governmental restraint. But "the power to exclude" is always based on governmental force.